Structure for attaching buttress to anvil and/or cartridge of surgical stapling instrument

ABSTRACT

An end effector of a surgical stapler includes first and second jaw members and a buttress releasably secured to the first jaw member. The first jaw member defines a first projection and a second projection distal of the first projection. The buttress defines a first slot and a first aperture distal of the first slot. The first slot is dimensioned to receive the first projection of the first jaw member, and the first aperture is dimensioned to receive the second projection of the first jaw member.

BACKGROUND Technical Field

The present disclosure relates to attachment systems for staple line buttress, and more particularly, to systems and methods for detachably securing staple line buttress to an anvil and/or a staple cartridge of a surgical stapling instrument.

Background of Related Art

Surgical stapling instruments are employed by surgeons to sequentially or simultaneously apply one or more rows of fasteners, e.g., staples or two-part fasteners, to body tissue for the purpose of joining segments of body tissue together. When stapling relatively thin or fragile tissues, it is important to effectively seal the staple line against air or fluid leakage. Additionally, it is often necessary to reinforce the staple line against the tissue to prevent tears in the tissue or pulling of the staples through the tissue. One method of preventing tears or pull through involves the placement of a biocompatible reinforcing material or “buttress” material, between the staple and the underlying tissue. In this method, a layer of buttress is placed against the tissue and the tissue is stapled in conventional manner.

Accordingly, new systems and methods that are reliable and that enable easy and efficient attachment and removal of a buttress to the surgical stapling instruments would be desirable.

SUMMARY

The present disclosure describes attachment structures for securing a buttress to a surgical stapler. The attachment structures demonstrate a practical approach to meeting the performance requirements and overcoming the usability challenges associated with buttress attachment and removal. In general, the present disclosure describes a surgical stapler that includes a handle assembly, an elongate member extending from the handle assembly, and an end effector operatively coupled with the handle assembly.

In accordance with an embodiment of the present disclosure, an end effector of a surgical stapler includes first and second jaw members and a buttress releasably secured to the first jaw member. The first jaw member is moveable relative to the second jaw member and defines a first projection and a second projection distal of the first projection. The buttress defines a first slot and a first aperture distal of the first slot. The first slot is dimensioned to receive the first projection of the first jaw member, and the first aperture is dimensioned to receive the second projection of the first jaw member.

In an embodiment, the buttress may be transitionable between an unexpanded state and an expanded state. A first distance is defined between the first slot and the first aperture in the unexpanded state, and a second distance is defined between the first and second projections of the first jaw member. In embodiments, the first distance may be less than the second distance.

In an embodiment, at least one of the first or second projections may define a groove. Alternatively, at least one of the first or second projections may include an hourglass profile.

In an embodiment, the first projection may be a hook.

In addition, the first jaw member may further include a flexible finger configured to engage the buttress. The buttress may further define a slit configured to securely engage the flexible finger of the first jaw member.

In accordance with another embodiment of the present disclosure, an end effector of a surgical stapler includes first and second jaw members and a buttress releasably secured to the first jaw member. The first jaw member defines a first projection and a second projection distal of the first projection and is moveable relative to the second jaw member. The buttress includes first and second bands configured to engage the first and second projections, respectively, of the first jaw member.

In an embodiment, at least one of the first or second bands may be elastic.

In an embodiment, the first jaw member may include an anvil. The second jaw member may include a staple cartridge.

In accordance with yet another embodiment of the present disclosure, an end effector of a surgical stapler includes first and second jaw members and a buttress releasably secured to the second jaw member. The first jaw member is moveable relative to the second jaw member and includes a finger extending from a surface of the first jaw member, and a projection extending from the surface of the first jaw member distal of the finger. The finger extends proximally outward from the surface and defines a gap with the surface. The buttress defines a first slot and a second slot distal of the first slot. The first slot is dimensioned to receive the finger, and the second slot is dimensioned to receive the projection.

In an embodiment, the buttress may be formed of an elastic material.

In an embodiment, the buttress may further include a tab at a distal portion of the buttress.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate embodiments of the disclosure and, together with a general description of the disclosure given above, and the detailed description of the embodiment(s) given below, serve to explain the principles of the disclosure, wherein:

FIG. 1 is a perspective view of a surgical stapling instrument including a buttress retention assembly for attaching staple line buttresses to an anvil and a staple cartridge of the surgical stapling instrument in accordance with an embodiment of the present disclosure;

FIG. 2 is a perspective view of a jaw assembly of the surgical stapling instrument of FIG. 1, illustrating a cartridge buttress mounted on the staple cartridge;

FIG. 3 is a perspective view of an anvil and an anvil buttress of the surgical stapling instrument in accordance with an embodiment of the present disclosure;

FIGS. 3A-C show various exemplary cross-sectional profiles for the boss of the anvil of FIG. 3;

FIG. 4 is a perspective view of an anvil and an anvil buttress in accordance with another embodiment of the present disclosure;

FIG. 5 is a perspective view of an anvil and an anvil buttress in accordance with yet another embodiment of the present disclosure;

FIG. 6 is an enlarged perspective view of the area of detail of FIG. 5 illustrating an anvil buttress retention assembly;

FIG. 7 is a perspective view of an anvil and an anvil buttress in accordance with still another embodiment of the present disclosure;

FIG. 8 is a perspective view of a cartridge and a cartridge buttress in accordance with an embodiment of the present disclosure;

FIG. 9 is a partial perspective view of a proximal portion of the staple cartridge of FIG. 8;

FIG. 10 is a partial perspective view of a distal portion of the staple cartridge of FIG. 8;

FIG. 11 is a partial cross-sectional view of the distal portion of the staple cartridge of FIG. 8, illustrating the cartridge buttress mounted on the staple cartridge;

FIG. 12 is a perspective view of the distal end of the surgical stapling instrument of FIG. 1 positioned about a tissue section;

FIG. 13 is a partial cross-sectional view of the distal end of the surgical stapling instrument positioned about the tissue section;

FIG. 14 is a partial cross-sectional view of the distal end of the surgical stapling instrument of FIG. 13;

FIG. 15 is a perspective view of a stapled and divided tissue section; and

FIG. 16 is a cross-sectional view taken along line 16-16 of FIG. 15.

DETAILED DESCRIPTION

Embodiments of the present disclosure are described in detail with reference to the drawings, in which like reference numerals designate identical or corresponding elements in each of the several views. As used herein, the term “distal” refers to that portion of a device that is farther from the user, while the term “proximal” refers to that portion of a device that is closer to the user.

With reference to FIG. 1, there is provided a surgical stapler 10 for use in stapling tissue and applying a layer of buttress between staples and underlying tissue. Surgical stapler 10 generally includes a handle 12 and an elongate tubular member 14 extending distally from handle 12. A jaw assembly 16 is mounted on a distal end 18 of elongate tubular member 14. Jaw assembly 16 includes an anvil 20 and a staple cartridge 22. Anvil 20 is movable between an open position configured to receive tissue between anvil 20 and staple cartridge 22, and a closed position configured to clamp tissue between anvil 20 and staple cartridge 22. In any of the embodiments disclosed herein, jaw assembly 16 may be attached to a mechanical or motorized handle, and staple cartridge 22 may be removable and replaceable.

With continued reference to FIG. 1, surgical stapler 10 includes a trigger 32 movably mounted on handle 12. Actuation of trigger 32 is configured to move anvil 20 from the open position to the closed position and subsequently actuate surgical stapler 10 to apply lines of staples 178 (FIG. 15) to tissue. In order to provide proper orientation of jaw assembly 16 relative to the tissue to be stapled, surgical stapler 10 is additionally provided with a rotation knob 34 mounted on handle 12. Rotation of rotation knob 34 about a longitudinal axis “A-A” of surgical stapler 10 rotates elongate tubular member 14 and jaw assembly 16 about longitudinal axis “A-A.”

With reference now to FIG. 2, a driver 36 is provided to move anvil 20 between the open and closed positions relative to staple cartridge 22. Driver 36 moves along a longitudinal slot 38 defined in anvil 20. A knife blade 77 (FIG. 13) is associated with driver 36 to cut tissue “T” (FIG. 12) captured between anvil 20 and staple cartridge 22 as driver 36 passes through longitudinal slot 38. In order to secure staples 178 (FIG. 13), provided by staple cartridge 22, about tissue “T” and anvil and cartridge buttresses 24, 26, anvil 20 is provided with longitudinally arranged rows of staple clinching or forming pockets 44 (FIG. 13) located on either side of longitudinal slot 38. Reference may be made to U.S. Pat. No. 7,128,253, filed on Jul. 20, 2005, entitled “Surgical Stapler,” the entire content of which is incorporated herein by reference, for a detailed discussion of the construction and operation of surgical stapler 10.

With reference to FIG. 3, anvil 20 and anvil buttress 24 together include an anvil buttress retention assembly 28 configured to detachably secure anvil buttress 24 on a contact surface 20 a of anvil 20 opposing staple cartridge 22 in accordance with an embodiment of the present disclosure. Such a configuration maintains anvil buttress 24 taut across contact surface 20 a.

With continued reference to FIG. 3, anvil buttress retention assembly 28 includes proximal and distal bosses 23 a, 23 b extending from contact surface 20 a of anvil 20 opposing staple cartridge 22. In addition, anvil buttress 24 defines proximal slots 25 a on a proximal portion thereof and distal bores 25 b on a distal portion thereof. Proximal slots 25 a of anvil buttress 24 are dimensioned to receive proximal bosses 23 a of anvil 20. Distal bores 25 b of anvil buttress 24 are configured to securely receive distal bosses 23 b of anvil 20.

Anvil buttress 24 may be formed at least in part of an elastic material so that anvil buttress 24 is transitionable between an unexpanded state and an expanded state. The distance between proximal slots 25 a and distal bores 25 b of anvil buttress 24 in the unexpanded state is shorter than the distance between proximal and distal bosses 23 a, 23 b of anvil 20 such that in order to place proximal and distal bosses 23 a, 23 b of anvil 20 into proximal slots 25 a and distal bores 25 b, respectively, anvil buttress 24 is stretched. Once anvil buttress 24 is secured to anvil 20, i.e., proximal and distal bosses 23 a, 23 b are received in proximal slots 25 a and distal bores 25 b, respectively, tension on anvil buttress 24 may be released and due to the elastic properties of anvil buttress 24, it is urged from the expanded state to back towards the unexpanded state, imparting tensional force on proximal and distal bosses 23 a, 23 b of anvil 20 thereby providing securement of anvil buttress 24 on anvil 20.

Specifically, in use, a clinician positions proximal bosses 23 a of anvil 20 within proximal slots 25 a of anvil buttress 24. Thereafter, the clinician stretches elastic anvil buttress 24 such that distal bores 25 b of anvil buttress 24 are positioned over distal bosses 23 b of anvil 20. When the clinician releases anvil buttress 24, the elastic properties retain anvil buttress 24 on anvil 20.

It is also contemplated that each of proximal and distal bosses 23 a, 23 b may define a circumferential groove 23 c (FIG. 3A) to enhance securement of anvil buttress 24 thereon. Alternatively, proximal and distal bosses 23 a, 23 b may include an hourglass profile (FIG. 3B) or a radially tapered profile (FIG. 3C) to further enhance securement of anvil buttress 24 on the respective proximal and distal bosses 23 a, 23 b and inhibit anvil buttress 24 from being dislodged from the respective proximal and distal bosses 23 a, 23 b.

With reference now to FIG. 4, there is provided an anvil buttress retention assembly 128 in accordance with another embodiment of the present disclosure. Anvil 20 is identical to the one described hereinabove and thus will not be described in detail to avoid obscuring the present disclosure in unnecessary detail. Anvil buttress retention assembly 128 includes proximal and distal bosses 23 a, 23 b extending from contact surface 20 a of anvil 20 opposing staple cartridge 22, and first and second bands or loops 130 a, 130 b affixed to an anvil buttress 124.

First and second bands 130 a, 130 b may be formed of an elastic material configured to conform to the placement of proximal and distal bosses 23 a, 23 b. Under such a configuration, first and second bands 130 a, 130 b may be selectively dimensioned to provide adequate tension or securement of anvil buttress 124 on proximal and distal bosses 23 a, 23 b. Alternatively, first and second bands 130 a, 130 b may be formed of a relatively rigid material that retains the original shape such as, e.g., U-shape. The relatively rigid first and second bands 130 a, 130 b may be affixed to anvil buttress 124 that is formed at least in part of elastic material, as described hereinabove. Under such a configuration, anvil buttress 124 is transitionable between a natural or unexpanded state and an expanded state. Anvil buttress 124 and first and second bands 130 a, 130 b may be dimensioned such that first band 130 a of anvil buttress 124 is first positioned by the clinician to place first band 130 a around respective proximal bosses 23 a, and then anvil buttress 124 is stretched to the expanded state to position second band 130 b around distal bosses 23 b. In this manner, once anvil buttress 124 is released by the clinician, anvil buttress 124 is urged toward the unexpanded state which, in turn, provides securement of anvil buttress 124 on anvil 20. It is also contemplated that each of proximal and distal bosses 23 a, 23 b may define a circumferential groove 23 c, as described hereinabove, to enhance securement of anvil buttress 124 thereon. In addition, proximal and distal bosses 23 a, 23 b may include an hourglass profile or a radially tapered profile to further enhance securement of first and second bands 130 a, 130 b thereon.

With reference now to FIGS. 5 and 6, there is provided an anvil buttress retention assembly 228 in accordance with another embodiment of the present disclosure. Anvil buttress retention assembly 228 includes proximal hooks 223 a extending proximally outward from a contact surface 220 a of anvil 220, and distal bosses 223 b extending from contact surface 220 a of anvil 220. In addition, anvil buttress 224 includes corresponding structures for the securement of anvil buttress 224 on anvil 220. In particular, anvil buttress 224 defines a pair of proximal slots 225 a dimensioned to receive respective proximal hooks 223 a therein, and a pair of distal bores 225 b dimensioned to receive distal bosses 223 b.

Anvil buttress 224 is formed at least in part of an elastic material such that anvil buttress 224 is transitionable between a natural or unexpanded state and an expanded state. A clinician initially positions proximal slots 225 a of anvil buttress 224 over proximal hooks 223 a, and then stretches anvil buttress 224 to place distal bosses 223 b in respective distal bores 225 b. When anvil buttress 224 is then released, it tends to return toward the unexpanded state, inhibiting disengagement of anvil buttress 224 from anvil 220.

As discussed hereinabove, each of distal bosses 223 b may define a circumferential groove 223 c to enhance securement of anvil buttress 224 thereon. Alternatively, distal bosses 223 b may include an hourglass profile or a radially tapered profile to further enhance securement of anvil buttress 224 thereon.

With reference now to FIG. 7, an anvil buttress retention assembly 328 in accordance with another embodiment of the present disclosure includes proximal hooks 323 a extending proximally outward from a contact surface 320 a of an anvil 320, and distal bosses 323 b extending from contact surface 320 a. In addition, anvil buttress retention assembly 328 further includes a finger 329 extending from a cavity 350 defined in anvil 320. Finger 329 includes a bend to enable slight flexing to facilitate engagement of finger 329 with anvil buttress 324. It is also contemplated that finger 329 may be formed of a flexible material to further facilitate engagement of finger 329 with anvil buttress 324.

Anvil buttress 324 includes corresponding structures for the securement of anvil buttress 324 on anvil 320. In particular, anvil buttress 324 defines proximal slots 325 a dimensioned to receive respective proximal hooks 323 a therein, and distal bores 325 b dimensioned to receive respective distal bosses 323 b. Furthermore, anvil buttress 324 defines a distal slot 323 c dimensioned to receive finger 329 to further enhance securement of anvil buttress 324 on anvil 320. While not specifically shown, additional fingers and corresponding slots may be provided depending on the nature of the buttress and the amount of frictional contact desired.

In addition, anvil buttress 324 further includes a tab 331 configured to facilitate gripping of anvil buttress 324 by the clinician. As discussed hereinabove, anvil buttress 324 may be formed at least in part of an elastic material such that anvil buttress 324 is first positioned over proximal hooks 323 a, and then stretched to engage distal bosses 323 b, and finger 329 to provide a tight securement with anvil 320. As discussed hereinabove, each of distal bosses 323 b may define a circumferential groove to enhance securement of anvil buttress 324 thereon. Alternatively, distal bosses 323 b may include an hourglass profile or a radially tapered profile to further enhance securement of anvil buttress 324 thereon.

While foregoing embodiments have been described with respect to securement of a buttress onto an anvil, it should of course be understood that the described structures may be used to secure a buttress to a staple cartridge of the end effector of a surgical stapler. Alternatively, both an anvil buttress and a cartridge buttress may both be employed. With reference now to FIG. 8, for example, a cartridge buttress retention assembly 428 in accordance with an embodiment of the present disclosure is configured to secure a cartridge buttress 26 on staple cartridge 422 prior to stapling of tissue. Cartridge buttress 26 reinforces and seals staple lines applied to tissue by surgical stapler 10. Staple cartridge 422 is provided with rows of staple pockets 412 and a knife channel 414 that passes longitudinally between rows of staple pockets 412.

With continued reference to FIGS. 8 and 9, cartridge buttress retention assembly 428 includes proximal fingers 423 a disposed on opposing sides of knife channel 414. Staple cartridge 422 includes a mount 433 that is transversely sloped or angled. Fingers 423 a extend proximally from mount 433. Mount 433 may be configured to provide a planar contact with cartridge buttress 26 thereon. A gap 450 is defined between each proximal finger 423 a and a contact surface 420 a of staple cartridge 422 to receive cartridge buttress 26.

With reference now to FIGS. 8 and 10, staple cartridge 422 defines a cavity 451 dimensioned to receive and/or support a finger 423 c. Cartridge buttress retention assembly 428 further includes a distal tooth 423 b extending from finger 423 c. Finger 423 c is configured for slight flexing to facilitate engagement of cartridge buttress 26 on distal tooth 423 b.

With reference now to FIGS. 8 and 11, cartridge buttress retention assembly 428 further includes proximal and distal slots 425 a, 425 b defined in cartridge buttress 26. Proximal slots 425 a are dimensioned to receive respective proximal fingers 423 a, and distal slot 425 b is dimensioned to receive distal tooth 423 b. Cartridge buttress 26 further includes a tab 455 configured to facilitate gripping of cartridge buttress 26 by the clinician. Cartridge buttress 26 may be formed at least in part of an elastic material such that cartridge buttress 26 is first positioned with proximal slots 425 a over proximal fingers 423 a and then stretched to position distal tooth 423 b within distal slot 425 b to provide tight securement with staple cartridge 422.

With reference now to FIGS. 12-16, jaw assembly 16 is positioned adjacent tissue “T” to be stapled. Driver 36 is in a proximal position relative to anvil slot 38 (FIG. 2). Staple cartridge 22 includes staples 178 positioned within respective staple pockets 18. Staples 178 are of a conventional type and include a backspan 182 having a pair of legs 184 and 186 extending from backspan 182. Legs 184 and 186 terminate in tissue penetrating tips 188 and 190. Pushers 192 are located within staple pockets 18 and are positioned between staples 178 and the path of a drive bar 194.

With particular reference to FIGS. 13 and 14, surgical stapler 10 is initially actuated by movement of trigger 32 relative to handle 12 (FIG. 1) causing driver 36 to move in the direction of arrow “B” and against sloped edge 40 of anvil 20 thereby causing anvil 20 to be moved to the closed position relative to staple cartridge 22. As drive bar 194 advances distally, drive bar 194 urges pushers 192 upwardly against backspans 182 of staples 178 driving staples 178 through cartridge buttress 26, tissue “T”, and anvil buttress 24 and towards staple clinching pockets 44 in anvil 20. Tissue penetrating tips 188 and 190 are bent within staple clinching pockets 44 in anvil 20 to thereby secure anvil buttress 24 against tissue “T” while backspan 182 secures cartridge buttress 26 against tissue “T”.

While not specifically shown, upon full actuation of surgical stapler 10, a knife blade associated with surgical stapler 10 and carried by driver 36 cuts tissue “T”, as well as anvil buttress 24 and cartridge buttress 26 between the rows of now clinched staples 178. Upon movement of anvil 20 to the open position spaced apart from staple cartridge 22, anvil buttress 24 pulls away from anvil 20 and cartridge buttress 26 pulls away from staple cartridge 22. The resulting tissue “T”, divided and stapled with staples 178 (FIGS. 15 and 16). Specifically, cartridge buttress 26 is secured against tissue “T” by backspans 182 of staples 178 and anvil buttress 24 is secured against tissue “T” by the now clinched tissue penetrating tips 188 and 190 of staples 178. In this manner, anvil buttress 24 and cartridge buttress 26 are stapled to tissue “T” thereby sealing and reinforcing the staple lines created by staples 178. The method of assembly and use of other embodiments of anvil buttress retention assemblies 128, 228, 328 and cartridge retention assembly 428 are substantially similar to the method described hereinabove with respect to anvil buttress retention assembly 28 and, thus, will not be described herein.

It is further contemplated that buttresses discussed hereinabove, may be made from any biocompatible natural or synthetic material. The material from which the buttress is formed may be bioabsorbable or non-bioabsorbable. It should of course be understood that any combination of natural, synthetic, bioabsorbable and non-bioabsorbable materials may be used to form the buttress.

Some non-limiting examples of materials from which the buttress may be made include but are not limited to poly(lactic acid), poly (glycolic acid), poly (hydroxybutyrate), poly (phosphazine), polyesters, polyethylene glycols, polyethylene oxides, polyacrylamides, polyhydroxyethylmethylacrylate, polyvinylpyrrolidone, polyvinyl alcohols, polyacrylic acid, polyacetate, polycaprolactone, polypropylene, aliphatic polyesters, glycerols, poly(amino acids), copoly (ether-esters), polyalkylene oxalates, polyamides, poly (iminocarbonates), polyalkylene oxalates, polyoxaesters, polyorthoesters, polyphosphazenes and copolymers, block copolymers, homopolymers, blends and combinations thereof.

In embodiments, natural biological polymers are used in forming the buttress. Suitable natural biological polymers include, but are not limited to, collagen, gelatin, fibrin, fibrinogen, elastin, keratin, albumin, hydroxyethyl cellulose, cellulose, hydroxypropyl cellulose, carboxyethyl cellulose, chitan, chitosan, and combinations thereof. In addition, the natural biological polymers may be combined with any of the other polymeric materials described herein to produce the buttress.

The buttress may be porous or non-porous, or combinations of porous and non-porous layers. Where the buttress is non-porous, buttress may retard or prevent tissue ingrowth from surrounding tissues thereby acting as an adhesion barrier and preventing the formation of unwanted scar tissue. Thus, in embodiments, the buttress possesses anti-adhesion properties. Techniques for forming non-porous layers from such materials are within the purview of those skilled in the art and include, for example, casting, molding and the like.

In embodiments, the buttress is porous and possesses hemostatic properties. Where the buttress is porous, it has openings or pores over at least a portion of a surface thereof. Suitable materials for forming the porous layer include, but are not limited to foams (e.g., open or closed cell foams). In embodiments, the pores may be in sufficient number and size so as to interconnect across the entire thickness of the porous layer. In other embodiments, the pores do not interconnect across the entire thickness of the porous layer. In yet other embodiments, the pores do not extend across the entire thickness of the porous layer, but rather are present at a portion of the surface thereof. In embodiments, the openings or pores are located on a portion of the surface of the porous layer, with other portions of the porous layer having a non-porous texture. Those skilled in the art reading the present disclosure will envision other pore distribution patterns and configurations for the porous layer.

Where the buttress is porous, the pores may be formed using any method suitable to forming a foam or sponge including, but not limited to the lyophilization or freeze-drying of a composition. Suitable techniques for making foams are within the purview of those skilled in the art. Porous buttresss can be at least 0.2 cm thick, in embodiments from about 0.3 to about 1.5 cm thick. Porous buttresss can have a density of not more than about 75 mg/cm² and, in embodiments below about 20 mg/cm². The size of the pores in the porous buttresss can be from about 20 μm to about 300 μm, in embodiments from about 100 μm to about 200 μm.

The buttress may also include a reinforcement member. The reinforcement member may be associated with a porous or non-porous layer or may be positioned between a non-porous layer and a porous layer of the buttress. Alternatively, the reinforcement member may be positioned entirely within one or more of the individual layers (i.e., embedded within the porous layer, the non-porous layer, or both) of the buttress. It is also envisioned that the reinforcement member may be positioned at the surface of one of the layers making up the buttress and, in embodiments, may be positioned at an exterior surface of the buttress.

Some suitable non-limiting examples of reinforcement members include fabrics, meshes, monofilaments, multifilament braids, chopped fibers (sometimes referred to in the art as staple fibers) and combinations thereof. Where the reinforcement member is a mesh, it may be prepared using any technique known to those skilled in the art, such as knitting, weaving, tatting, knipling or the like. Where monofilaments or multifilament braids are used as the reinforcement member, the monofilaments or multifilament braids may be oriented in any desired manner. For example, the monofilaments or multifilament braids may be randomly positioned with respect to each other within the buttress. As another example, the monofilaments or multifilament braids may be oriented in a common direction within the buttress. Where chopped fibers are used as the reinforcement member, the chopped fibers may be oriented in any desired manner. For example, the chopped fibers may be randomly oriented or may be oriented in a common direction. The chopped fibers can thus form a non-woven material, such as a mat or a felt. The chopped fibers may be joined together (e.g., by heat fusing) or they may be unattached to each other. The chopped fibers may be of any suitable length. For example, the chopped may be from 0.1 mm to 100 mm in length, in embodiments, 0.4 mm to 50 mm in length. In an illustrative embodiment, the buttress has randomly oriented chopped fibers that have not been previously fused together embedded within in the buttress.

It is envisioned that the reinforcement member may be formed from any bioabsorbable, non-bioabsorbable, natural, or synthetic material previously described herein and combinations thereof. Where monofilaments or multifilament braids are used as the reinforcement member, any commercially available suture material may advantageously be employed as the reinforcement member.

In embodiments, at least one bioactive agent may be combined with the buttress and/or any of the individual components (the porous layer, the non-porous layer and/or the reinforcement member) used to construct the buttress. In these embodiments, the buttress can also serve as a vehicle for delivery of the bioactive agent. The term “bioactive agent”, as used herein, is used in its broadest sense and includes any substance or mixture of substances that have clinical use. Consequently, bioactive agents may or may not have pharmacological activity per se, e.g., a dye, or fragrance. Alternatively a bioactive agent could be any agent which provides a therapeutic or prophylactic effect such as a compound that affects or participates IN tissue growth, cell growth, or cell differentiation.

Examples of classes of bioactive agents which may be utilized in accordance with the present disclosure include anti-adhesives, antimicrobials, analgesics, antipyretics, anesthetics, antiepileptics, antihistamines, anti-inflammatories, cardiovascular drugs, diagnostic agents, sympathomimetics, cholinomimetics, antimuscarinics, antispasmodics, hormones, growth factors, muscle relaxants, adrenergic neuron blockers, antineoplastics, immunogenic agents, immunosuppressants, gastrointestinal drugs, diuretics, steroids, lipids, lipopolysaccharides, polysaccharides, and enzymes. It is also intended that combinations of bioactive agents may be used.

Anti-adhesive or anti-adhesion agents can be used to prevent adhesions from forming between the buttress and the surrounding tissues opposite the target tissue. Some examples of these agents include, but are not limited to poly(vinyl pyrrolidone), carboxymethyl cellulose, hyaluronic acid, polyethylene oxide, poly vinyl alcohols and combinations thereof.

Suitable antimicrobial agents which may be included as a bioactive agent in the buttress of the present disclosure include triclosan, also known as 2,4,4′-trichloro-2′-hydroxydiphenyl ether, chlorhexidine and its salts, including chlorhexidine acetate, chlorhexidine gluconate, chlorhexidine hydrochloride, and chlorhexidine sulfate, silver and its salts, including silver acetate, silver benzoate, silver carbonate, silver citrate, silver iodate, silver iodide, silver lactate, silver laurate, silver nitrate, silver oxide, silver palmitate, silver protein, and silver sulfadiazine, polymyxin, tetracycline, aminoglycosides, such as tobramycin and gentamicin, rifampicin, bacitracin, neomycin, chloramphenicol, miconazole, quinolones such as oxolinic acid, norfloxacin, nalidixic acid, pefloxacin, enoxacin and ciprofloxacin, penicillins such as oxacillin and pipracil, nonoxynol 9, fusidic acid, cephalosporins, and combinations thereof. In addition, antimicrobial proteins and peptides such as bovine lactoferrin and lactoferricin B may be included as a bioactive agent in the bioactive coating of the present disclosure.

Other bioactive agents which may be included as a bioactive agent in the buttress in accordance with the present disclosure include: local anesthetics; non-steroidal antifertility agents; parasympathomimetic agents; psychotherapeutic agents; tranquilizers; decongestants; sedative hypnotics; steroids; sulfonamides; sympathomimetic agents; vaccines; vitamins; antimalarials; anti-migraine agents; anti-parkinson agents such as L-dopa; anti-spasmodics; anticholinergic agents (e.g. oxybutynin); antitussives; bronchodilators; cardiovascular agents such as coronary vasodilators and nitroglycerin; alkaloids; analgesics; narcotics such as codeine, dihydrocodeinone, meperidine, morphine and the like; non-narcotics such as salicylates, aspirin, acetaminophen, d-propoxyphene and the like; opioid receptor antagonists, such as naltrexone and naloxone; anti-cancer agents; anti-convulsants; anti-emetics; antihistamines; anti-inflammatory agents such as hormonal agents, hydrocortisone, prednisolone, prednisone, non-hormonal agents, allopurinol, indomethacin, phenylbutazone and the like; prostaglandins and cytotoxic drugs; estrogens; antibacterials; antibiotics; anti-fungals; anti-virals; anticoagulants; anticonvulsants; antidepressants; antihistamines; and immunological agents.

Other examples of suitable bioactive agents which may be included in the coating composition include viruses and cells, peptides, polypeptides and proteins, analogs, muteins, and active fragments thereof, such as immunoglobulins, antibodies, cytokines (e.g. lymphokines, monokines, chemokines), blood clotting factors, hemopoietic factors, interleukins (IL-2, IL-3, IL-4, IL-6), interferons (β-IFN, (α-IFN and γ-IFN), erythropoietin, nucleases, tumor necrosis factor, colony stimulating factors (e.g., GCSF, GM-CSF, MCSF), insulin, anti-tumor agents and tumor suppressors, blood proteins, gonadotropins (e.g., FSH, LH, CG, etc.), hormones and hormone analogs (e.g., growth hormone), vaccines (e.g., tumoral, bacterial and viral antigens); somatostatin; antigens; blood coagulation factors; growth factors (e.g., nerve growth factor, insulin-like growth factor); protein inhibitors, protein antagonists, and protein agonists; nucleic acids, such as antisense molecules, DNA and RNA; oligonucleotides; polynucleotides; and ribozymes.

Persons skilled in the art will understand that the structures and methods specifically described herein and shown in the accompanying figures are non-limiting exemplary embodiments, and that the description, disclosure, and figures should be construed merely as exemplary of particular embodiments. For example, bosses and projections may be slightly larger in size than the apertures, thereby providing an interference fit upon insertion of the bosses or projections into the apertures. The bosses, projections, and the corresponding apertures may have any geometry best suited for retaining the bosses and projections within the apertures. In addition, various numbers of fingers or projections may be provided to increase the frictional contact between a jaw member and an associated buttress.

In addition, the buttress may be formed in its entirety or only in part from an elastic material, provided that the buttress may be stretched a sufficient distance to engage both the proximal and distal projections on the anvil or staple cartridge. For example, the buttress may include one or more bands of elastic material anywhere along its length, with the remainder of the buttress made from an inelastic material. As another example, the buttress may be made of a combination of materials that are relatively more elastic and materials that are relatively less elastic. In any of the embodiments disclosed herein, the anvil and the staple cartridge may be part of a robotic surgical system.

It is contemplated that a removable and replaceable cartridge can be pre-loaded with a buttress assembly and that the cartridge can be loaded into a surgical stapling reload. The first surgical buttress is supplied already attached to the staple cartridge by the various methods mentioned above. A suture attachment method as disclosed in WO 2008/109125, the disclosure of which is hereby incorporated by reference herein, can be used. The first and second buttresses are also attached to springs. The buttress assembly is loaded into the reload by pinching the springs against the cartridge, sliding the cartridge into the channel, and securing it in the channel, such as snapping the cartridge into place. The springs hold the second buttress in place and help to keep the jaws of the reload open. After firing the staples, the buttresses pull away from the jaws of the stapler, or a knife provided in the reload cuts away the connection, such as disclosed in WO 2008/109125 where sutures are cut by knife blades. The spent cartridge is then removed and a fresh cartridge having a new buttress assembly, or without the buttress assembly, can be loaded into the reload.

A reload with a removable and replaceable staple cartridge is disclosed in U.S. Pat. No. 9,016,539, the disclosure of which is hereby incorporated by reference herein.

It is to be understood, therefore, that the present disclosure is not limited to the precise embodiments described, and that various other changes and modifications may be effected by one skilled in the art without departing from the scope or spirit of the disclosure. Additionally, the elements and features shown or described in connection with certain embodiments may be combined with the elements and features of certain other embodiments without departing from the scope of the present disclosure, and that such modifications and variations are also included within the scope of the present disclosure. Accordingly, the subject matter of the present disclosure is not limited by what has been particularly shown and described. 

What is claimed is:
 1. An end effector of a surgical stapler, comprising: first and second jaw members, the first jaw member moveable relative to the second jaw member, the first jaw member defining a first projection and a second projection distal of the first projection; and a buttress transitionable between an unexpanded state and an expanded state and defining a first slot at a proximal portion thereof and a first aperture distal of the first slot, the first slot dimensioned to receive the first projection of the first jaw member, the first aperture dimensioned to receive the second projection of the first jaw member, the first aperture positioned on the buttress to receive the second projection when the buttress is in the expanded state.
 2. The end effector according to claim 1, wherein a first distance is defined between the first slot and the first aperture in the unexpanded state, and a second distance is defined between the first and second projections, the first distance being shorter than the second distance.
 3. The end effector according to claim 1, wherein at least one of the first or second projections defines a groove.
 4. The end effector according to claim 1, wherein at least one of the first or second projections includes an hourglass profile.
 5. The end effector according to claim 1, wherein the first projection is a hook.
 6. The end effector according to claim 1, wherein the first jaw member further includes a flexible finger distal of the second projection.
 7. The end effector according to claim 6, wherein the buttress further defines a slit configured to engage the flexible finger of the first jaw member.
 8. The end effector according to claim 1, wherein the first jaw member includes an anvil.
 9. An end effector of a surgical stapler, comprising: first and second jaw members, the first jaw member moveable relative to the second jaw member, the first jaw member defining a first projection and a second projection distal of the first projection; and a buttress including first and second bands configured to engage the first and second projections, respectively.
 10. The end effector according to claim 9, wherein the buttress is transitionable between an unexpanded state and an expanded state.
 11. The end effector according to claim 9, wherein a first distance is defined between the first and second bands in the unexpanded state, and a second distance is defined between the first and second projections, the first distance being shorter than the second distance.
 12. The end effector according to claim 9, wherein at least one of the first or second bands is elastic.
 13. The end effector according to claim 9, wherein at least one of the first or second projections includes an hourglass profile.
 14. The end effector according to claim 9, wherein the first jaw member includes an anvil.
 15. The end effector according to claim 14, wherein the second jaw member includes a staple cartridge.
 16. An end effector of a surgical stapler, comprising: first and second jaw members, the first jaw member moveable relative to the second jaw member, the second jaw member including a finger extending from a surface of the second jaw member, and a projection distal of the finger, the finger extending proximally outward from the surface and defining a gap with the surface; and a buttress defining a first slot and a second slot distal of the first slot, the first slot dimensioned to receive the finger of the second jaw member and the second slot dimensioned to receive the projection of the second jaw member.
 17. The end effector according to claim 16, wherein the buttress is formed at least in part of an elastic material.
 18. The end effector according to claim 16, wherein the buttress further includes a tab at a distal portion of the buttress.
 19. A method of securing a buttress to a jaw member of an end effector of a surgical stapler, the method comprising: positioning a first slot of the buttress over a first projection on the jaw of the end effector, the buttress made at least in part of an elastic material; stretching the buttress to position a first aperture of the buttress over a second projection on the jaw of the end effector, the second projection being distal of the first projection; and releasing tension on the buttress to secure the buttress to the jaw member.
 20. The method according to claim 19, wherein positioning comprises positioning a pair of slots over a pair of first projections, and stretching comprises positioning a pair of first apertures over a pair of second projections. 